Borrowings (Details) $ in Thousands			12 Months Ended
	Feb. 13, 2019 USD ($)	Aug. 18, 2017 USD ($)	Dec. 31, 2020 USD ($) counterparty		Dec. 31, 2019 USD ($) counterparty		Dec. 31, 2018 USD ($) counterparty
Borrowings [Line Items]
Total secured borrowings			$ 2,300,000		$ 3,200,000		$ 1,911,000
Concentration Risk, Reverse Repurchase Agreements							2100.00%
Number of Counterparties With Concentration Risk, Reverse Repurchase Agreements | counterparty							1
Number of Counterparties with Outstanding Reverse Repurchase Agreements | counterparty			24		28		23
Financial Instruments transferred as collateral for repurchase agreements			$ 1,831,000		$ 2,763,000		$ 1,790,000
Collateral on repurchase agreements, unsettled sales			$ 1,400		64,700
Pledged Financial Instruments, Not Separately Reported, Securities For Repurchase Agreements Unsettled							$ 86,700
Repurchase Agreements amount at risk threshold			10.00%				10.00%
Other secured borrowings			$ 51,062	[1]	150,334	[1]	$ 114,100
Other secured borrowings, at fair value			$ 754,921	[1]	$ 594,396	[1]	297,948
Long-term Debt, Fair Value							$ 86,000
Minimum
Borrowings [Line Items]
Reverse Repurchase Agreements Maturity			30 days				30 days
Repurchase agreements, remaining days to maturity			4 days		2 days		2 days
Repurchase Agreements Interest Rate			0.20%		0.15%		23.00%
Maximum
Borrowings [Line Items]
Reverse Repurchase Agreements Maturity			180 days				180 days
Repurchase agreements, remaining days to maturity			516 days		882 days		871 days
Repurchase Agreements Interest Rate			5.00%		5.20%		607.00%
Reverse repurchase agreements
Borrowings [Line Items]
Cash collateral posted for securities sold under agreements to repurchase			$ 28,900		$ 31,000		$ 17,000
Security Owned and Pledged as Collateral, Fair Value					200		200
Securitized residential mortgage loans
Borrowings [Line Items]
Fair Value of Assets Transfered and Accounted for as Secured Borrowings			801,300		629,100
Secured borrowing recourse facility collateralized by unsecured loan portfolio
Borrowings [Line Items]
Other secured borrowings			$ 8,700		$ 16,000		$ 13,200
Debt Instrument, Interest Rate, Effective Rate			2.30%		3.85%
Debt Instrument, Interest Rate, Stated Percentage							4.72%
Secured borrowing recourse facility collateralized by unsecured loan portfolio | Unsecured loans
Borrowings [Line Items]
Fair Value of Assets Transfered and Accounted for as Secured Borrowings			$ 11,500		$ 22,300		$ 20,300
Non-QM loan securitization
Borrowings [Line Items]
Other secured borrowings					$ 594,400		$ 297,900
Debt Instrument, Interest Rate, Effective Rate			2.43%		3.19%
Debt Instrument, Interest Rate, Stated Percentage							3.72%
Secured borrowing facility collateralized by unsecured loan portfolio
Borrowings [Line Items]
Other secured borrowings			$ 7,000		$ 102,500		$ 101,000
Debt Instrument, Interest Rate, Effective Rate			2.25%		4.01%
Debt Instrument, Interest Rate, Stated Percentage							4.68%
Secured borrowing facility collateralized by unsecured loan portfolio | Unsecured loans
Borrowings [Line Items]
Fair Value of Assets Transfered and Accounted for as Secured Borrowings			$ 31,800		$ 144,100		$ 149,000
Secured borrowing facility collateralized by ABS backed by consumer loans [Member]
Borrowings [Line Items]
Other secured borrowings			$ 28,700		$ 31,800
Debt Instrument, Interest Rate, Effective Rate			5.22%		5.23%
Fair Value of Assets Transfered and Accounted for as Secured Borrowings			$ 44,500		$ 47,900
Commercial mortgage loans
Borrowings [Line Items]
Other secured borrowings			6,700
Fair Value of Assets Transfered and Accounted for as Secured Borrowings			$ 17,300
Senior Notes
Borrowings [Line Items]
Debt Instrument, Interest Rate, Effective Rate			5.80%
Debt Instrument, Face Amount	$ 86,000	$ 86,000
Proceeds from Debt, Net of Issuance Costs		$ 84,700
Debt Instrument, Interest Rate, Stated Percentage	5.50%	5.25%					5.55%
Redemption percentage	100.00%	100.00%
Debt Instrument, Maturity Date		Sep. 01, 2022

[1] Ellington Financial Inc.'s Consolidated Balance Sheet includes assets and liabilities of variable interest entities it has consolidated. See Note 9 for additional details on Ellington Financial Inc.'s consolidated variable interest entities.